Churchill, Hugh Olen HillBestwick, Andrew J.Harlow, Jennifer W.Kuemmeth, FerdinandMarcos, DavidStwertka, Carolyn H.Watson, Susan K.Marcus, C2011-08-152009Churchill, Hugh Olen Hill, Andrew J. Bestwick, Jennifer W. Harlow, Ferdinand Kuemmeth, David Marcos, Carolyn H. Stwertka, Susan K. Watson, and Charles Masamed Marcus. 2009. Electron-nuclear interaction in 13C nanotube double quantum dots. Nature Physics 5(5): 321-326.1745-2473http://nrs.harvard.edu/urn-3:HUL.InstRepos:5110752For coherent electron spins, hyperfine coupling to nuclei in the host material can either be a dominant source of unwanted spin decoherence or, if controlled effectively, a resource enabling storage and retrieval of quantum information. To investigate the effect of a controllable nuclear environment on the evolution of confined electron spins, we have fabricated and measured gate-defined double quantum dots with integrated charge sensors made from single-walled carbon nanotubes with a variable concentration of \(^{13}C\) (nuclear spin \((I=\frac{1}{2})\) among the majority zero-nuclear-spin \(^{12}C\) atoms. We observe strong isotope effects in spin-blockaded transport, and from the magnetic field dependence estimate the hyperfine coupling in \(^{13}C\) nanotubes to be of the order of \(100 \mu eV\), two orders of magnitude larger than anticipated. \(^{13}C\)-enhanced nanotubes are an interesting system for spin-based quantum information processing and memory: the \(^{13}C\) nuclei differ from those in the substrate, are naturally confined to one dimension, lack quadrupolar coupling and have a readily controllable concentration from less than one to \(10^5\) per electron.en-UScarbon nanotubesspinJournal Article2011-08-1510.1038/nphys1247